composition
over
inheritance
object
class
ES6
We now have 'class'.
But do we want to use it?
Inheritance
Vehicle
Land Vehicle
Car
Ferrari
Composition
Engine
Ferrari
Tire
Mirror
Break
Seat
But inheritance
works pretty well
in your example!
OK, but
what happens if...
Vehicle
Land Vehicle
Engine
Amphicar
Tire
Mirror
Break
Seat
skrew propeller
rudder
Other problems w.
class inheritance
-
fragile base class
-
diamond problem
So how can I use
composition in Javascript?
With pure Javascript
Oh wait, there's a lib
for that...
but it sucks.
(by Eric Elliott)
What's a stamp?
[A] composable factory function [...] that returns object instances[...].
https://github.com/stampit-org/stamp-specification
Installation
$ npm install stampit
Let's build a stamp
var stampit = require('stampit');
var myStamp =
stampit()
.props()
.refs()
.init()
.methods()
.static()
stampit()
.refs()
.props()
.init()
.methods()
.static()
Add instance safe,
deeply merged properties to
the objects created from the stamp
stampit()
.refs()
.props()
.init()
.methods()
.static()
Add properties which are passed
by reference to the objects
created from the stamp
stampit()
.refs()
.props()
.init()
.methods()
.static()
Add private data
and privileged methods to
the objects created from the stamp
stampit()
.refs()
.props()
.init()
.methods()
.static()
Add public methods to
the objects created from the stamp
stampit()
.refs()
.props()
.init()
.methods()
.static()
Add methods to the stamp,
but not to the objects
created from the stamp
DEMO
Additional facts
-
also available for react
https://github.com/stampit-org/react-stamp
-
can convert javascript constructor functions
with convertConstructor()
-
created as example for the book
'Programming Javascript Applications'
(see http://bit.ly/pjsa-free-ebook)
I wanna tinker too
http://bit.ly/ES6BP
